Process for removing nitrates and perchlorates from fluids
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-03-07
- Publication Date
- 2026-03-04
Smart Images
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Abstract
Description
[Technical field]
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 317,372, filed March 7, 2022, which is incorporated by reference in its entirety herein.
[0002] Field The present disclosure relates generally to methods and products for treating water. More specifically, the present disclosure relates to the removal of nitrates and perchlorates from water sources in a streamlined reclamation process.
[0003] background Water treatment is a vital aspect of modern society, and materials and processes to improve the efficiency and effectiveness of water treatment are constantly evolving. There are many potential contaminants that must be removed by water treatment systems, and a variety of systems, methods, and compositions are often employed to remove or reduce the harm caused by various contaminants. Traditional materials for water treatment, contaminant removal, or harm reduction include activated carbon, ion exchange resins, chemical treatments, and catalysts.
[0004] Examples of known contaminants include nitrates and perchlorates from water sources. Each contaminant is understood in the art to be different from the other, and therefore, prior to the present disclosure, those skilled in the art typically choose two separate systems to remove perchlorates first and then nitrates. Attempts have also been made to remove both nitrates and perchlorates in one system using one or more nitrate-specific resins, but the industry consensus is that contacting nitrate-specific resins with perchlorate-containing fluid streams significantly reduces the lifespan of the nitrate-specific resins.
[0005] Thus, the current state of the art requires a process that requires at least two separate adsorbent beds, each containing at least one nitrate or perchlorate specific resin, to remove first the perchlorate and then the nitrate with a perchlorate specific resin followed by a nitrate specific resin, which requires significant time and physical space to remove these contaminants. Summary of the Invention
[0006] In some aspects, the technology described herein relates to a method of removing nitrate and perchlorate from a fluid containing nitrate and perchlorate, the method comprising contacting the fluid with a single resin to cause the single resin to bind the nitrate and perchlorate, and regenerating the single resin by a regeneration process comprising contacting the single resin with a salt solution, wherein the regeneration removes a substantial portion of the nitrate contained within the single resin but does not remove a substantial portion of the perchlorate contained within the single resin, and wherein the single resin comprises a nitrate-specific resin and does not comprise a perchlorate-specific resin.
[0007] In some aspects, the technology described herein relates to methods, wherein the fluid is water.
[0008] In some embodiments, the technology described herein relates to methods, wherein the water is selected from the group including groundwater, wastewater, industrial wastewater, drinking water, agricultural runoff, ballast water, aquaculture water, and combinations thereof.
[0009] In some embodiments, the technology described herein relates to methods in which the fluid contains up to about 50 ppm nitrates prior to removal.
[0010] In some embodiments, the technology described herein relates to methods in which the fluid after removal contains up to about 10 ppm nitrates.
[0011] In some embodiments, the technology described herein relates to methods in which the fluid contains up to about 35 ppb of perchlorate prior to removal.
[0012] In some embodiments, the technology described herein relates to methods in which the fluid contains up to about 5 ppb of perchlorate prior to removal.
[0013] In some embodiments, the technology described herein relates to methods in which the single resin is a strong base anion resin.
[0014] In some embodiments, the technology described herein relates to methods where the regeneration process uses about 6 pounds to about 9 pounds of salt per cubic foot of a single resin.
[0015] In some embodiments, the technology described herein relates to methods that further comprise a subsequent contacting step and a subsequent regenerating step.
[0016] In some embodiments, the technology described herein relates to methods in which subsequent contacting steps and subsequent regeneration steps are repeated until the single resin is no longer able to remove perchlorate from the fluid.
[0017] In some embodiments, the technology described herein relates to methods in which subsequent contacting steps and subsequent regeneration steps are repeated until a single resin is no longer able to remove nitrates from the fluid.
[0018] In some embodiments, the technology described herein relates to methods whereby the regenerating step does not result in the bound perchlorate on a single resin being bound to a different portion of the single resin.
[0019] In some aspects, the technology described herein relates to an intermediate resin product that includes a body of a single resin and an amount of perchlorate that cannot be removed by regenerating the single resin with salt regeneration, where the single resin includes a nitrate-specific resin and does not include a perchlorate-specific resin.
[0020] In some embodiments, the technology described herein relates to an intermediate resin article, where a first portion of the body of the unitary resin article is completely saturated with perchlorate and is incapable of retaining additional perchlorate or nitrate, and a second portion of the body of the unitary resin article is substantially free of bound perchlorate and is capable of retaining additional perchlorate or nitrate upon contact. [Brief description of the drawings]
[0021] Aspects, features, benefits, and advantages of the embodiments described herein will become apparent with regard to the following description, the appended claims, and the accompanying drawings.
[0022] [Figure 1] The figure is a table of results from a water treatment facility using the methods of the present disclosure showing the effectiveness of nitrate and perchlorate removal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] This disclosure provides examples of removing nitrates and perchlorates from water, as well as examples of regenerating the resins used for removal.
[0024] The present disclosure describes a method for removing both nitrate and perchlorate from a fluid source, including, in some embodiments, water in a water treatment facility, using a nitrate-specific resin. It is conventionally understood in the art that the removal of nitrate and perchlorate requires two separate steps: first, contacting the fluid with a perchlorate-specific resin to remove the perchlorate, thereby obtaining a perchlorate-removed effluent, and then contacting the perchlorate-removed effluent with a nitrate-specific resin to remove the nitrate, thereby obtaining a perchlorate- and nitrate-removed effluent. Conventionally, attempts have been made to remove both nitrate and perchlorate from a fluid source by contacting the fluid with only a single resin in a single bed, but this conventional technique has been found to result in a short resin life. Furthermore, the use of a single resin typically results in extensive contamination of the resin with perchlorate, which cannot be removed by salt regeneration. Thus, it is now standard in the art to use two separate resins to remove nitrate and perchlorate.
[0025] It was therefore surprising and unexpected that the inventors discovered that both perchlorate and nitrate can be successfully removed from a fluid with a single resin with little or no loss in the operational life of the single resin. Disclosed herein is a method for removing both nitrate and perchlorate by contacting at least one fluid with a single resin. In some embodiments, the single resin is a nitrate removal resin, and the inventors have surprisingly discovered that the resin can remove perchlorate and maintain nitrate and perchlorate removal performance for a longer life than is realized by the prior art. Conventional single resins, when contacted with a fluid containing perchlorate, are typically replaced after less than one year of use. However, the disclosed method allows the single resin to achieve an operational life of more than five years with minimal or no loss in nitrate and perchlorate removal performance.
[0026] In all embodiments, both nitrates and perchlorates are removed from the fluid stream in whole or in part by contacting the fluid stream with the single resin. The single resin may be a nitrate removal resin, also called a nitrate-specific resin. In this context, "single resin" means that there is no separate or dedicated resin for removing perchlorates, although there may be additional resins for other purposes. In some embodiments, the single resin of the present disclosure includes a nitrate-specific resin (which may be a strong base anion resin) and does not include a perchlorate-specific resin, e.g., a resin specifically designed for the removal of perchlorates. In some embodiments, the single resin of the present disclosure includes a nitrate-specific resin and further includes one or more additional resins designed for the removal of compounds such as chromium, perfluoroalkyl and polyfluoroalkyl substances (PFAS), arsenic, antimony, and does not include a perchlorate-specific resin.
[0027] The fluid stream is not limited, but is typically a fluid that has not been treated or has received only minimal treatment for undesirable compounds. For example, the fluid stream may include one or more of groundwater, wastewater, industrial wastewater, drinking water, agricultural runoff, ballast water, aquaculture water, or a combination of one or more of the preceding fluid streams. The influent fluid stream to be treated typically includes an amount of nitrate of up to about 50 ppm, e.g., up to about 10 ppm, up to about 20 ppm, up to about 30 ppm, up to about 40 ppm, or any range of amounts of nitrate including one or more of the preceding values as endpoints, such as about 10 ppm to about 50 ppm, about 10 ppm to about 40 ppm, about 10 ppm to about 30 ppm, about 10 ppm to about 20 ppm. After contacting the fluid with the single resin, the resulting effluent may contain at most about 10 ppm nitrates (as N), e.g., at most 8 ppm, at most 6 ppm, at most 4 ppm, at most 2 ppm.
[0028] The fluid stream may also contain other compounds such as perchlorate. The amount of perchlorate is not particularly limited and may be an amount of up to about 35 ppb, such as up to about 10 ppb, up to about 20 ppb, up to about 30 ppb, or any range formed from any of the aforementioned values, such as about 10 ppb to about 35 ppb, about 20 ppb to about 35 ppb, about 30 ppb to about 35 ppb. After contacting the fluid with the single resin, the amount of perchlorate is reduced in the effluent formed, and in some cases, the resulting effluent may contain up to 10 ppb of perchlorate, such as up to about 8 ppb, up to about 6 ppb, up to about 5 ppb, up to about 4 ppb, or up to about 2 ppb, or a range formed from two or more of the aforementioned values.
[0029] After contacting the fluid with the single resin, nitrate and perchlorate are bound to the single resin, resulting in a wastewater with reduced amounts of nitrate. Although the single resin is often selected to adsorb nitrate, the single resin also adsorbs perchlorate. In some embodiments, the amount of nitrate adsorbed is greater than the amount of perchlorate adsorbed, for example, when nitrate is present at about 50 ppm in the influent fluid and perchlorate is present at about 35 ppb in the same influent fluid. Thus, in certain embodiments, the amount of nitrate adsorbed to the single resin, measured as a weight percent, is greater than the amount of perchlorate. The fluid contacted with the single resin can be recovered for use or further processing.
[0030] In some configurations, the single resin is a nitrate-specific resin, such as a strong base anion (SBA) resin. The polymer used to form the single resin is not particularly limited and may be, for example, one or more of polystyrene, poly(divinylbenzene), copolymers of styrene and divinylbenzene (DVB), or acrylic copolymers. In some embodiments, the single resin is a polymer functionalized with quaternary ammonium groups, such as quaternized trialkylamines. Exemplary trialkylamines that may be present as quaternary groups on the polymers of the present disclosure include, but are not limited to, trimethylamine, triethylamine, tripropylamine, tributylamine, dimethylethanolamine, diisopropylethylamine, and the like. The inventors have surprisingly discovered that by selecting a nitrate-specific SBA resin as the single resin, the single resin continues to maintain excellent performance in removing both nitrates and perchlorates from the liquid. Without wishing to be bound by theory, it is believed that the nitrate-specific SBA resin prevents the diffusion of bound perchlorates within the resin while the resin is being regenerated by salt regeneration. Because of this phenomenon, a column of nitrate-specific strong base anion (SBA) resin will retain significant amounts of bound perchlorate adjacent or proximate to the inlet of a fluid containing nitrate and perchlorate, but this perchlorate will not diffuse or otherwise contaminate the portion of the resin near the outlet of the fluid. Thus, the effluent leaving a bed of nitrate-specific SBA retains low levels of perchlorate contamination.
[0031] The single resin can be regenerated to recover some of its adsorption capacity. Regeneration is accomplished through a regeneration process, which in some embodiments is a salt regeneration, in which a salt solution containing at least one of sodium chloride or potassium chloride contacts the single resin. The regeneration process can include washing, flushing, or otherwise contacting the single resin with the salt solution. The concentration of the salt solution is not particularly limited and can be from about 6 pounds of salt to about 9 pounds of salt per cubic foot of resin being regenerated, such as about 6 pounds, about 6.5 pounds, about 7 pounds, about 7.5 pounds, about 8 pounds, about 8.5 pounds, about 9 pounds, or any range or value therein.
[0032] During regeneration, the nitrates bound to the single resin are removed and the nitrate-binding capacity of the single resin is restored or substantially restored. Regeneration can remove all or a portion of the nitrates contained within the single resin. In some embodiments, regeneration removes a substantial portion of the nitrates contained within the single resin, where a substantial portion is considered to be some or most, but not all, of the nitrates contained within the single resin. Perchlorates bound to the single resin are not removed by such action in some embodiments and remain bound to the single resin. Considering the relatively small amount of perchlorates compared to the large amount of nitrates, it is understood that the capacity loss of the single resin due to bound perchlorates in each sequence of treatment and regeneration steps is low enough that it does not substantially affect the overall capacity of the single resin. In some embodiments, regeneration does not cause the bound perchlorates to bind to another portion of the single resin.
[0033] In some embodiments, regeneration produces an intermediate single resin product that includes a body of the single resin as described herein and an amount of perchlorate that cannot be removed by regeneration of the single resin by salt regeneration, such as the regeneration methods described herein. In some embodiments, a first portion of the body of the single resin product is completely saturated with perchlorate and cannot retain additional perchlorate or nitrate, and a second portion of the body of the single resin product has substantially no bound perchlorate and can retain additional perchlorate or nitrate when contacted, such as by contact with a fluid containing perchlorate and / or nitrate.
[0034] In some embodiments, the methods disclosed herein may include a subsequent contacting step, a subsequent regenerating step, or a combination thereof. The methods disclosed herein may include one or more subsequent regenerating and / or contacting steps, with 1, 2, 3, 4, 5, or more subsequent contacting and / or regenerating steps being included in the disclosed methods.
[0035] After multiple treatment and regeneration cycles, the amount of perchlorate loaded onto the single resin increases to the point where the single resin cannot remove any more perchlorate (the single resin is completely saturated with perchlorate), even though the single resin is regenerated and can load more nitrate. At this point, if the single resin can no longer remove perchlorate and / or nitrate from the fluid, the single resin can be discarded and replaced, and the process described above repeated.
[0036] In some embodiments, the methods of the present disclosure extend the operational life of a single resin, enabling a single resin to effectively remove nitrates and perchlorates from a fluid stream for a period of at least about 5 years, at least about 6 years, at least about 7 years, at least about 8 years, at least about 9 years, at least about 10 years, etc.
[0037] Working Example Example 1
[0038] At a water treatment facility, the amount of nitrate and perchlorate was measured before water treatment. The amount of nitrate in several wells before treatment was 15 mg / L to 24 mg / L (equivalent to ppm). After treatment with a nitrate-specific resin using the method of the present disclosure, the amount of nitrate was measured to be 1.8 mg / L to 2.4 mg / L (ppm).
[0039] The amount of perchlorate in the wells before treatment was measured to be between 2 μg / L and 19 μg / L (equivalent to ppb). After treatment with the nitrate-specific resin using the method of the present disclosure, the amount of perchlorate was below the detection limit of 0.5 ppb, suggesting that the amount of perchlorate in the water tested after treatment was less than 0.5 ppb.
[0040] Further water quality test data is shown in the figure.
[0041] Without wishing to be bound by theory, it is proposed that the method of the present disclosure, which includes using a single resin to remove both nitrates and perchlorates from a fluid stream, and regenerating the single resin to remove the nitrates bound thereto, can significantly extend the operating life of the single resin.
[0042] The present disclosure is not limited to the particular systems, apparatus, and methods described. The terminology used herein is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope.
[0043] In the above detailed description, reference is made to the accompanying drawings, which form a part of this specification. In the drawings, similar reference numerals generally identify similar components unless the context dictates otherwise. The exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments can be used and other changes can be made without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that aspects of the present disclosure, as generally described herein and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are expressly contemplated herein.
[0044] The present disclosure is not limited in terms of the specific embodiments described in this application, which are intended as examples of various aspects. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope thereof. In addition to those enumerated herein, functionally equivalent methods and apparatuses within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to be included within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to specific methods, reagents, compounds, compositions, or biological systems. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
[0045] With respect to the use of virtually any plural and / or singular term herein, one of ordinary skill in the art can translate from plural to singular and / or from singular to plural as appropriate to the context and / or application. Various singular / plural permutations may be expressly provided herein for clarity.
[0046] In general, those skilled in the art will understand that the terms used in this specification, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including, but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "including, but not limited to," etc.). Although various compositions, methods, and devices are described with terms "comprising" various components or steps (interpreted to mean "including, but not limited to"), the compositions, methods, and devices can also "consist essentially of" or "consist of" various components and steps, and such terms should be interpreted to define essentially closed groups of members. Those skilled in the art will further understand that if a specific number of recitations of the introduced claims are intended, such intent will be explicitly recited in the claims, and in the absence of such recitation, no such intent exists.
[0047] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly indicates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by prior invention. As used herein, the term "comprising" means "including, but not limited to."
[0048] As used herein, the term "about" means plus or minus 10% of the number with which it is used. Thus, "about 50" means in the range of 45 to 55.
[0049] The term "ppm" is commonly understood to mean "parts per million" and is well known in the art as a standard unit of concentration. Similarly, the term "ppb" means "parts per billion" and is well known in the art as a standard unit of concentration.
[0050] For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitation. However, the use of such phrases should not be construed as meaning that the introduction of a claim repetition with the indefinite article "a" or "an" limits a particular claim that includes such an introduced claim repetition to embodiments that include only one such repetition, even if the same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be construed to mean "at least one" or "one or more"), and the same applies to the use of definite articles used to introduce the claim recitation.
[0051] In addition, even if a particular number of introduced claims is explicitly recited, one of ordinary skill in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the mere recitation of "two iterations" without other modifiers means at least two iterations, or more than two iterations). Furthermore, when an idiom similar to "at least one of A, B, and C, etc." is used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the idiom (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together). When phrases similar to "at least one of A, B, or C, etc." are used, such configurations are generally intended in the sense that one of ordinary skill in the art would understand the phrase (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). One of ordinary skill in the art will further understand that substantially any conjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" is understood to include the possibilities of "A" or "B," or "A and B."
[0052] In addition, where features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will recognize that the disclosure is thereby also described in terms of any individual members or subgroups of members of the Markush group.
[0053] As will be appreciated by those of skill in the art, all ranges disclosed herein encompass all possible subranges and combinations of subranges thereof for any purpose, including in terms of providing a written description. Any recited range can be readily recognized as fully descriptive and allowing for the same range to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third, upper third, etc. As will also be appreciated by those of skill in the art, all phrases such as "up to," "at least," etc. refer to ranges that are inclusive of the recited numbers and that can then be broken down into subranges as described above. Finally, as will be appreciated by those of skill in the art, ranges include individual members. Thus, for example, a group having 1-3 compounds refers to a group having 1, 2, or 3 compounds. Similarly, a group having 1-5 cells refers to a group having 1, 2, 3, 4, or 5 compounds, etc.
[0054] The various features and functions disclosed above, or alternatives thereof, may be combined into many other different systems or applications. Various alternatives, modifications, variations, or improvements not presently foreseen or anticipated, may subsequently be made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.
Claims
1. 1. A method for removing nitrates and perchlorates from a fluid containing nitrates and perchlorates, the method comprising: contacting the fluid with a single resin to bind the nitrates and the perchlorates to the single resin; and regenerating the single resin by a regeneration process including contacting the single resin with a salt solution, the regenerating removing a substantial portion of the nitrates contained within the single resin, but not removing a substantial portion of the perchlorates contained within the single resin; Including, The method, wherein the single resin comprises a nitrate-specific resin and no perchlorate-specific resin.
2. The method of claim 1 , wherein the fluid is water.
3. 3. The method of claim 2, wherein the water is selected from the group including groundwater, wastewater, industrial wastewater, drinking water, agricultural runoff, ballast water, aquaculture water, and combinations thereof.
4. 10. The method of claim 1, wherein the fluid contains up to about 50 ppm nitrates prior to removal.
5. 10. The method of claim 1, wherein the fluid contains up to about 10 ppm nitrates after removal.
6. 10. The method of claim 1, wherein the fluid contains up to about 35 ppb perchlorate prior to removal.
7. 10. The method of claim 1, wherein the fluid contains up to about 5 ppb perchlorate after removal.
8. 2. The method of claim 1, wherein the single resin is a strong base anion resin.
9. 9. The method of claim 8, wherein the regeneration process uses about 6 pounds to about 9 pounds of salt per cubic foot of single resin.
10. 10. The method of claim 1, further comprising a subsequent contacting step and a subsequent regenerating step.
11. 11. The method of claim 10, wherein the subsequent contacting and regenerating steps are repeated until the single resin is no longer able to remove perchlorate from the fluid.
12. 11. The method of claim 10, wherein the subsequent contacting and subsequent regenerating steps are repeated until the single resin is no longer able to remove nitrates from the fluid.
13. 2. The method of claim 1, wherein the regenerating step does not cause bound perchlorate on the single resin to bind to a different portion of the single resin.
14. 1. An intermediate resin product comprising a body of a single resin and an amount of perchlorate that cannot be removed by regenerating said single resin with salt regeneration, said single resin comprising a nitrate-specific resin and no perchlorate-specific resin.
15. 15. The intermediate resin article of claim 14, wherein a first portion of the body of the single resin article is completely saturated with perchlorate and cannot retain additional perchlorate or nitrate, and a second portion of the body of the single resin article is substantially free of bound perchlorate and can retain additional perchlorate or nitrate upon contact.